weak spot vs weakness

weak spot and weakness both are nouns.

Word	Noun	Adjective	Verb	Adverb
weak spot	Yes	No	No	No
weakness	Yes	No	No	No

As nouns, weakness is a hypernym of weak spot; that is, weakness is a word with a broader meaning than weak spot:

weak spot: a place of especial vulnerability
weakness: the property of lacking physical or mental strength; liability to failure under pressure or stress or strain

weak spot (noun)	weakness (noun)
a place of especial vulnerability	the property of lacking physical or mental strength; liability to failure under pressure or stress or strain
	powerlessness revealed by an inability to act
	a penchant for something even though it might not be good for you
	a flaw or weak point
	the condition of being financially weak